TriNewt Battery EXPOSED!

[Wicho]

Here's a link to a post I made on MTBR.com regarding the TriNewt Battery. I got one and opened it up to rebuild it.

Enjoy.

http://forums.mtbr.com/showthread.php?t=504370

BELOW IS WHAT I POSTED. I posted the link above so you can follow any discussion that may happen over there.


So I got my hands on an old, dead TriNewt battery. It gave the blue and red switch lights simultaneously. Of course, the battery came with a charger, light head, helmet mount, extension cable and case. Gotta love REI used gear sales.

Started taking it apart today.

Enjoy the pics!

http://img11.imageshack.us/gal.php?g=img4955.jpg
http://img11.imageshack.us/gal.php?g=img4960.jpg
http://img11.imageshack.us/gal.php?g=img4970.jpg
http://img11.imageshack.us/gal.php?g=img4979j.jpg

There's a whole bunch of silicone holding everything in place inside, and I got the case open by using really big pliers to apply pressure around the seam. I wrapped a towel around the case to cushion everything. You HAVE to start cracking the case open from the bottom (the part opposite the connector/switch). Once you have the case open, gently cut away some of the silicone and push the batteries away from the sides in a rolling motion with your fingers. Patience is key here - don't try to do it too fast.

Now I'm off to Batteries Plus for some replacement cells. Muahahahaha!!!

 

[cave dave]

18650's?

 

[Wicho]

Yup, 18650's.

Batteries plus didn't have any - said they could order them, but...I'll just order them on-line tomorrow.

 

[nleahcim]

So why are you so sure that it's the batteries that need replacing? The PCB looks fairly complicated - lots of parts that could have died on it...

 

[Wicho]

Good question - early TriNewt batteries were known for having problems with bad cells from everything I've read and this one is from mid-2007. While there is a chance there is something else wrong with it as you mention, I'm willing to take a $35 gamble on buying new cells. Nothing appeared to be fried on the PCB just by looking at it - yes, I know that's not a very scientific way of looking at things.

Worst case scenario, I use the new cells for something else. The light was dirt cheap and was a good way of getting something I've always wanted to try and rebuild.

 

[nleahcim]

Good question - early TriNewt batteries were known for having problems with bad cells from everything I've read and this one is from mid-2007. While there is a chance there is something else wrong with it as you mention, I'm willing to take a $35 gamble on buying new cells. Nothing appeared to be fried on the PCB just by looking at it - yes, I know that's not a very scientific way of looking at things.

Worst case scenario, I use the new cells for something else. The light was dirt cheap and was a good way of getting something I've always wanted to try and rebuild.

You should try measuring the voltage across the individual cells - see if any are completely out of balance. I'm not sure what the specific failure these guys have had - but when I've seen Li-ion packs fail it's typically 1 cell in the pack - not the whole pack - so you can often find one cell that is at a completely different voltage than the others.